Hylians are depicted as usually having blue or blue-grey eyes, and both Wario and Waluigi have blue-grey eyes.

Both of them have pointed ears.

Lower classes generally wear casual clothes and the men usually wear broad-brimmed hats for protection. (granted the signature hats they wear aren't really broad brimmed but I'm sure they get the job done)

Finally, these images

While not Wario or Waluigi, it may point to something deeper as the two Mario brothers in disguise. Or perhaps Mario and Luigi are the disguises of Ingo and Talon in the Mushroom Kingdom.

Mainly I want to see if there's any further possible proof that Waluigi, Wario, Mario, and/or Luigi could be Hylian. But feel free to dispute it too.